A matching couple in China. Photo posted on Flickr by Tom Spender.

How can you tell the difference between a serious couple and "just good friends" in Korea, China or Japan? Easy. A pair of really committed lovers will be wearing the same outfit.

The fad has become so popular in Eastern Asia that perfectly matched couples fill the fashion pages of magazines, and shops are tailoring outfits that come as a pair.

A matching couple in the streets of Seoul, South Korea. Posted on Flickr by "Chuhuicha".

“Public displays of affection remain a taboo here. Matching outfits are a kind of substitute”

Crystal Tao is from Chongqing, central China. She writes about fashion on her blog, "Love Love China: everything about Chinese girls".

Matching outfits is definitely an Asian phenomenon. But it's not mainstream. Matching couples certainly don't go unnoticed by passers-by here.

The fashion is mainly targeted at heterosexual teens and young people. I found one of the comments left on my blog post about matching outfits quite funny; the person labelled the style as ‘gay'. In fact, I can't imagine two boys wearing matching outfits!

You might think that only fashionable or non-conformist people would wear matching outfits. But it's not true. Take my elder cousin. She's far from teenaged, she's not particularly daring, but she is definitely in love with her husband. Just a few weeks ago I saw them wearing the same black and white T-shirt. I was quite shocked at first. But then I asked myself if I would do the same. Yes, I thought. People say that when you're in love, you're a little bit crazy - so why not?

Most cases of matching outfits include T-shirts. In my opinion, T-shirts are like a personal ad space which allow people to show a little bit of their personality, whether it be showing their passion for Metallica, cursing Microsoft, or just to say ‘Shit happens'. Asians use T-shirts to show other kinds of things; to boast about their relationship.

Most Westerners think that matching outfits are childish. They can only imagine parents dressing their twin kids in the same stuff. Maybe it's because collectivity is valued as more important in Asian society. Another explanation is that public displays of affection remain something of a taboo here. Matching outfits are a kind of substitute for the lack of kisses and hugs they can share in public.

Of course if people break up, they don't wear the clothes again. The same applies to any meaningful item that a couple shares together. But these are just clothes. How about people who get a tattoo of their lover's name?"

A couple on Jeju Island, South Korea. Posted on Flickr by "Sanbon".

China. Posted on Flickr by Tom Spender.

Songnae, South Korea. Posted on Flickr by "radianman".

In the Yeouido district of Seoul. Posted on Flickr by "wmdeneve".

A Beijing shop specialised in matching outfits. Posted on Flickr by "Retroleum".

Yurakucho district, Tokyo, Japan. Posted on Flickr by "Jamesjustin".

South Korea. Photo posted on the The Daily Kimchi blog.

South Korea. Photo posted on the The Daily Kimchi blog.